PhD on Reactions of Ozone with Water Matrix Components: Reactive Sites and Oxidation By-product formation

Posted onSeptember 17, 2018 byAdmin

EPFL has an opening PhD position. This fellowship is available for all students around the world. Applicants should apply as soon as possible.

The Drinking Water Chemistry group of the Department of Water Resources & Drinking Water (W+T) at Eawag, the Swiss Federal Institute of Aquatic Science and Technology and the Laboratory for Water Quality and Treatment at the Swiss Federal Institute of Technology, Lausanne (EPFL) are offering two PhD positions

PhD on Reactions of ozone with water matrix components: reactive sites and oxidation by-product formation

The application of ozone for disinfection or abatement of micropollutants during treatment of drinking water and wastewater is accompanied by ozone reactions with matrix components such as dissolved organic matter (DOM). During ozonation, DOM is typically the main sink for ozone, which is decisive for the efficiency of this process. The reactions with electron-rich moieties such as phenols or olefins also lead to the formation of undesired oxidation by-products such as low molecular weight aldehydes and ketones or quinones. Furthermore, the reactions of ozone with nitrogen-containing moieties in the DOM may lead to the formation of potentially toxic oxygen-containing nitrogenous oxidation by-products such as nitro or nitroso compounds and N-oxides. These problems are possibly aggravated by ozone applications to impaired waters as for enhanced wastewater treatment or water reuse. In these water matrixes, DOM concentrations and the content of nitrogen-containing moieties are typically much higher than in conventional water sources. This will lead to an enhanced ozone consumption and a potential shift to nitrogenous oxidation by-products. Based on this assessment, the main objectives of the two PhD theses are:
- Quantification of the reactions of phenolic and olefinic dissolved organic matter moieties with ozone to determine their effect on ozone consumption and the formation of potentially toxic oxygen-containing oxidation by-products (e.g., low molecular weight aldehydes and ketones or quinones).
- Quantification of the reactions of nitrogenous moieties in the DOM with ozone and the formation of potentially toxic nitrogen-containing oxidation by-products (e.g., C-/N-nitroso or nitro compounds and N-oxides).

These objectives will be addressed as follows:

To better understand ozone consumption by DOM and the formation of oxidation by-products, concentrations of reactive DOM moieties will be quantified by combining kinetic modeling, kinetic experiments with various oxidants and enhanced analytical tools including isotope ratio mass spectrometry and high-resolution mass spectrometry. Overall, these studies will yield a better understanding of the reactions of DOM with ozone and with other oxidants and provide tools to quantify ozone-reactive moieties and the formation of organic oxidation by-products. The results from this study are crucial to optimize ozonation processes to minimize human and environmental health impacts. The gained information will be important for environmental scientists and engineers and federal and cantonal authorities.

The ideal candidates will have a strong experimental background in either chemistry or environmental sciences with a master's degree.

The PhD students will work at the Drinking Water Chemistry Group at Eawag or the Laboratory for Water Quality and Treatment at EPFL under the supervision of Prof. Urs von Gunten. The PhD students will be enrolled in the doctoral program of the School of Architecture, Environmental and Civil Engineering (ENAC) at EPFL. The two positions are fully funded through a 4-year period. The preferred start is November 2018.

Eawag and EPFL offer good research and working environments and are committed to promoting equal opportunities for women and men and to support the compatibility of family and work. State-of-the-art experimental facilities and highly interdisciplinary research environments are available for both PhD projects at Eawag and EPFL.

Deadline for applications is August 31, 2018. The positions will remain open until suitable candidates are found. Your application should include a CV, academic transcripts (with undergraduate grades), a statement of research interests and motivation and names and contact information of 2-3 academic referees (please do not include letters with the application).